When can a deduction of up to 0.20 be applied in respect to dismounts on bars?

Deductions of up to 0.20 can be applied to dismounts on the bars for incomplete twists or for piked down dismounts, as these directly affect the execution and appearance of the dismount. Incomplete twists imply that the gymnast did not fully complete a required rotation, impacting the overall quality of the routine. Similarly, a piked down dismount does not demonstrate the required form and control expected from a gymnast at this level.

While under-rotation of elements and excessive trunk movements can also lead to deductions, the specific context of the question is focused on the direct issues with dismounts on bars, making incomplete twists or improper dismount form the most relevant point for these deductions. Thus, option A specifically addresses situations that warrant a deduction up to 0.20 for dismounts on bars, aligning closely with gymnastic scoring criteria.